TY - JOUR
T1 - Localization and interaural time difference (ITD) thresholds for cochlear implant recipients with preserved acoustic hearing in the implanted ear
AU - Gifford, René H.
AU - Grantham, D. Wesley
AU - Sheffield, Sterling W.
AU - Davis, Timothy J.
AU - Dwyer, Robert
AU - Dorman, Michael
N1 - Funding Information:
This research was supported by grant R01 DC009404 from the National Institute on Deafness and Other Communication Disorders . Portions of these data were presented at the Hearing Preservation Symposium in Baltimore, MD, April 30, 2012, the 2012 International Hearing Aid Research Conference in Tahoe City, California, August 8–12, 2012, the American Speech-Language-Hearing Association, Atlanta, GA, November 15-17, 2012, and the Ultimate Midwinter Otolaryngology meeting, Vail, CO, February 2-6, 2014. Data collection and management via REDCap was supported by Vanderbilt Institute for Clinical and Translational Research grant support (UL1 TR000445 from NCATS/NIH).
PY - 2014/6
Y1 - 2014/6
N2 - The purpose of this study was to investigate horizontal plane localization and interaural time difference (ITD) thresholds for 14 adult cochlear implant recipients with hearing preservation in the implanted ear. Localization to broadband noise was assessed in an anechoic chamber with a 33-loudspeaker array extending from-90 to+90°. Three listening conditions were tested including bilateral hearing aids, bimodal (implant+contralateral hearing aid) and best aided (implant+bilateral hearing aids). ITD thresholds were assessed, under headphones, for low-frequency stimuli including a 250-Hz tone and bandpass noise (100-900Hz). Localization, in overall rms error, was significantly poorer in the bimodal condition (mean: 60.2°) as compared to both bilateral hearing aids (mean: 46.1°) and the best-aided condition (mean: 43.4°). ITD thresholds were assessed for the same 14 adult implant recipients as well as 5 normal-hearing adults. ITD thresholds were highly variable across the implant recipients ranging from the range of normal to ITDs not present in real-world listening environments (range: 43 to over 1600μs). ITD thresholds were significantly correlated with localization, the degree of interaural asymmetry in low-frequency hearing, and the degree of hearing preservation related benefit in the speech reception threshold (SRT). These data suggest that implant recipients with hearing preservation in the implanted ear have access to binaural cues and that the sensitivity to ITDs is significantly correlated with localization and degree of preserved hearing in the implanted ear.
AB - The purpose of this study was to investigate horizontal plane localization and interaural time difference (ITD) thresholds for 14 adult cochlear implant recipients with hearing preservation in the implanted ear. Localization to broadband noise was assessed in an anechoic chamber with a 33-loudspeaker array extending from-90 to+90°. Three listening conditions were tested including bilateral hearing aids, bimodal (implant+contralateral hearing aid) and best aided (implant+bilateral hearing aids). ITD thresholds were assessed, under headphones, for low-frequency stimuli including a 250-Hz tone and bandpass noise (100-900Hz). Localization, in overall rms error, was significantly poorer in the bimodal condition (mean: 60.2°) as compared to both bilateral hearing aids (mean: 46.1°) and the best-aided condition (mean: 43.4°). ITD thresholds were assessed for the same 14 adult implant recipients as well as 5 normal-hearing adults. ITD thresholds were highly variable across the implant recipients ranging from the range of normal to ITDs not present in real-world listening environments (range: 43 to over 1600μs). ITD thresholds were significantly correlated with localization, the degree of interaural asymmetry in low-frequency hearing, and the degree of hearing preservation related benefit in the speech reception threshold (SRT). These data suggest that implant recipients with hearing preservation in the implanted ear have access to binaural cues and that the sensitivity to ITDs is significantly correlated with localization and degree of preserved hearing in the implanted ear.
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U2 - 10.1016/j.heares.2014.02.007
DO - 10.1016/j.heares.2014.02.007
M3 - Article
C2 - 24607490
AN - SCOPUS:84897069467
SN - 0378-5955
VL - 312
SP - 28
EP - 37
JO - Hearing Research
JF - Hearing Research
ER -